[PATCH v2] power: domain: ti: fix ti_pd_get() to return after verifying transition

[Siddharth Vadapalli]

On Fri, 2025-11-14 at 20:32 +0530, Siddharth Vadapalli wrote:

Kindly ignore this patch. I will post the v3 patch including the test logs
on the platforms implementing PCIe Boot (this patch is required for such
platforms to avoid waiting for 1 millisecond after a power-on request).

Regards,
Siddharth.

> The helper function "ti_pd_get()" is responsible for powering on a
> domain if it is powered off. In the current implementation, if a power
> domain is determined to be powered off - no prior users and the PDCTL
> register indicates that the user desired state is OFF, then powering on
> the domain constitutes setting 'PDCTL_STATE_ON' field of the PDCTL
> register.
> 
> While the current implementation indeed requests the power domain to be
> transition to the ON state, the helper function "ti_pd_get()" doesn't
> verify that the power domain has 'transitioned' to the ON state before
> returning to its caller. As a result, it is possible that the device(s)
> belonging to the power domain may be accessed before it is truly powered
> on, leading to a bus abort.
> 
> Fix this by waiting for the power domain to transition to the ON state
> by using "ti_pd_wait()" before returning from "ti_pd_get()".
> 
> Fixes: 144464bd2c67 ("power: domain: Introduce driver for raw TI K3 PDs")
> Signed-off-by: Siddharth Vadapalli <s-vadapalli at ti.com>
> ---
> 
> Hello,
> 
> This patch is based on commit
> 6c2f2d9aa63 Merge branch 'master' of git://source.denx.de/u-boot-usb
> of the master branch of Mainline U-Boot.
> 
> v1 of this patch is at:
> https://lore.kernel.org/r/20251114114611.57032-1-s-vadapalli@ti.com/
> Changes since v1:
> - Replaced the following:
> 	+	ret = ti_pd_wait(psc_pd);
> 	+	if (ret)
> 	+		return ret;
> 	+
> 		return 0;
>   with:
>   	return ti_pd_wait(psc_pd);
> - Updated the last paragraph of commit message by mentioning
>   "ti_pd_wait()".
> 
> Regards,
> Siddharth.
> 
>  drivers/power/domain/ti-power-domain.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/power/domain/ti-power-domain.c b/drivers/power/domain/ti-power-domain.c
> index c3519307340..09d9e1b3159 100644
> --- a/drivers/power/domain/ti-power-domain.c
> +++ b/drivers/power/domain/ti-power-domain.c
> @@ -227,7 +227,7 @@ static int ti_pd_get(struct ti_pd *pd)
>  
>  	pd_write(pdctl, pd, PSC_PDCTL);
>  
> -	return 0;
> +	return ti_pd_wait(psc_pd);
>  }
>  
>  static int ti_pd_put(struct ti_pd *pd)